Avalanche forecast

Northwest Coastal

Mar 19 – 20, 2016Avalanche Canada
View on map
Archived · expired 11 years ago

Avalanche danger

Mon
Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
Open full map

Highlights

Extra caution is needed in areas in the northern part of the region where buried persistent weaknesses remain active.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–3
    Recently easterly outflow winds may have created fresh wind slabs in exposed terrain.

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–5
    Natural cornice releases are more likely during periods of sun exposure and warming. A falling cornice chunk could trigger a large slab on the slope below.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    3–6
    Persistent weaknesses have recently been reacting to cornice triggers in the northern part of the region. Keep these in mind if you're riding near Bear Pass or Ningunsaw Pass.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Light flurries and moderate southerly winds are forecast for Sunday and Monday. A mix and sun and cloud and light winds are expected on Tuesday. Freezing levels should sit at about 1300m for the forecast period.

Avalanche Summary

On Thursday, there were reports of natural and explosive-triggered cornice falls, primarily from areas north of Stewart and near Ningunsaw Pass. Many of these triggered persistent slabs with the largest results (size 3-3.5) occurring on NE-NW aspects. Observations from the southern part of the region were limited, but in the past few days there were a few reports of natural and human triggered storm slabs to size 2 just below ridgecrest in north facing alpine terrain.

Snowpack Summary

Easterly winds have redistributed the surface snow forming fresh wind slabs in exposed terrain. On sheltered and shady slopes there is 20-40 cm of settled dry (and faceting) powder, possibly capped by surface hoar. On south aspects, the recent storm snow may be sitting on a sun crust. Lower elevations and south aspects are going through daily melt-freeze cycles. A layer of surface hoar or melt-freeze crust buried on March 3 is down 70-100cm and has been recently reactive in the areas north of Stewart. An older crust/facet layer buried in early February can now be found down over a meter but this layer has been dormant for several weeks.

Regions covered